Beware of the Watchdog
by OtakuChef
Summary: Current Earl Lucy Heartfilia stands on top of Fiore's Underworld as the Queen's Watchdog. With her demon butler Natsu Dragneel by her side, they make sure dark society always remain in the dark. (Black Butler AU)


**_Summary_ :** Current Earl Lucy Heartfilia stands on top of Fiore's Underworld as the Queen's Watchdog. With her demon butler Natsu Dragneel by her side, they make sure dark society always remain in the dark.

 ** _A/N:_ ** Hello! I really hope you'll like this Black Butler AU. This all started when I imagined Lucy and demon!Natsu forming a contract that it didn't leave my mind. I just had to write it.

FYI, this AU is going to be a collection of loosely-connected one-shots. You can expect for more chapters after this one. There will be mature content in the future chapters too.

Also, the cover pic was drawn by my good friend swordbreaker from tumblr. Make sure you check out her blog to see the full comic which goes with this chapter.

 _ **Disclaimer:**_ Fairy Tail and Black Butler belong to Hiro Mashima and Yana Toboso respectively. This is merely a work of a fan with a very active imagination and an undying love for Natsu, Lucy and their relationship.

* * *

The horses neighed as the coachman pulled on their reins to stop. He heard the door creak as it opened and the carriage rocked when his patron dismounted onto the pavement. Stroking his moustache, Baron Everlue gave the coachman a dismissive glance, silently telling that his services are no longer needed. The man bowed in return and spurred the horses into motion once again. There was no need to come back later.

Everlue looked up and around the massive manor house in front of him. He had a bumpy ride through the thick forest that surrounded the area so it didn't surprise him anymore to see more thick foliage around the main house. The Heartfilia Manor looked grand and looming. Anyone would know at first glance that the house belonged to a distinguished noble you don't want to cross. And as he walked the rest of the path to the main door, he remembered the rumors that surrounded the residents of the manor.

The Heartfilias run Heart Kreuz, the leading company in dressmaking in the whole of Fiore. Nobles clamor for their extensive line of elegant dresses and gowns while the commoners love the practicality of their cheaper pieces. But beneath the good public image, only a few know that the Heartfilia name alone could strike fear among the members of Fiore's Underworld. They prowl the dark society as the Queen's Watchdog, always ready to eliminate anything that worried their kind-hearted Queen.

"But that ends today." Everlue thought as he stroked his moustache once again. "Tonight Fiore's Underworld will have a new order ~boyo."

* * *

"You're really great at this." Lucy said as she looked at her reflection on the mirror. Aquarius, one of her maids, had her golden hair pulled and twisted into a bun atop her head with a sapphire rose ornament holding it in place. It's a perfect match to the Prussian blue dress she chose to wear for the evening.

"A simple task." The maid stated. "I used to do Lady Layla's hair for events like this during her time."

A small smile formed on Lucy's lips. "I know." she said softly. "Still, thank you for your work, Aquarius." She can still remember how beautiful her late mother was before she died. She was graceful and kind, always looking out for Lucy when she was little. Everybody was drawn to her despite being a member of the Heartfilia family. Sometimes she couldn't help but miss her.

The knock on the door pulled her back to reality. "Come in." she said"

"Baron Everlue has arrived." Natsu, the head butler of the house, announced as he entered the room. "He is currently waiting at the entrance hall."

"Are you finished with your preparations as well?" She asked him as she turned on her chair to look at him. Her eyes did an involuntary once-over, noting that he looked dashing like always in his uniform.

Unfortunately for her, Natsu noticed this and smirked as he answered her question. "Yes, everything is ready for you, Lady Lucy."

She recognized the teasing smirk and blushed at getting caught. Another reminder for her to break this habit of giving him reasons to tease her. "Very well," she said as her cheeks burned, "I will meet them in a minute."

"As you wish." He smirked once more before bowing and exiting the room.

Lucy swore she heard a faint laugh behind the closed door.

She drew a deep breath before standing up. She looked at her full reflection to check for anything amiss and found none. There was only one thing to add to her evening ensemble. She shed the white fingerless gloves she is currently wearing and slipped on the black gloves Natsu brought her.

Aquarius, who was standing behind her, bowed her head as she walked out the door.

It's time for work.

* * *

Lucy resisted the urge to roll her eyes the moment she saw her guest as she descended upon the stairs. Her guest looked very awkward in his ill-fitting tuxedo and ridiculous curled moustache.

She paused on the first landing and announced her presence to him. "Thank you for coming. I am Lucy Heartfilia, the current earl." The surprised looked on her guest's face almost cracked her up which was very understandable. After all, she introduced herself as an earl, not a countess. The heads of the Heartfilia House were always given the title of Earl, no matter what their gender is.

She reluctantly held out her hand to him when the man bowed. "I am Baron Edgar Everlue, my Lady. Pleased to make your acquaintance." He said as he kissed the back of her hand.

Thankfully, she always wore gloves. He was more repulsive up close. She would have gagged if she actually felt his breath and lips on her skin.

"The pleasure's all mine." She flashed him a deceptively sweet smile. From the corner of her eyes, she could see her butler shamelessly smirking at her, again. Oh, she will have a word with him later.

"Forgive me, my Lady. I was under the impression that I will be meeting a man tonight that I am left speechless at your beauty and grace." Everlue said, still holding her hand.

She could only keep smiling, despite the blaring need to draw back her hand.

"It's a shame, really." the man continued, his smile slowly turning into a smirk. "If I have known, I would have prepared something different for you tonight, ~boyo."

 _"Boyo?"_ Lucy asked silently. _"Did he really just –"_

She gasped loudly when Everlue tugged her hand. She fell right into his chest and felt the wind knocked out of her when she bumped into something hard. A gun holster.

His other hand worked quickly and drew a revolver which he pointed at Natsu.

"Careful, Mr. Butler." warned Everlue. "One wrong step and you'll be scrubbing out your lady's brains on the carpet." He then shoved the revolver onto Lucy's temple.

Natsu quietly held up his hand and stepped back.

"Very good." Everlue stepped back as well, dragging Lucy with him to the door. Lucy resisted, grunting and shaking in his grip. "Better behave Miss Earl or there will be a bloody hole on your arm." He whispered angrily. They were already out the door when two men in black suits approached the baron. "Take care of the butler and all other witnesses." He ordered them.

Lucy saw this as a chance to escape. She hit the attacker's chin with her head. It hurt a lot but the loud "OW!" from the old man was satisfying. She hiked up her skirts and started to run back to the manor.

Unfortunately, Everlue recovered quickly and had a long reach. She got her by her hair, undoing Aquarius' hard work. Golden tresses spilled forth as the hair ornament fell on the ground, followed by a strike to her nape. Everything turned dark afterwards.

* * *

Her head was throbbing when she woke up. "Natsu?" she asked, as she tried to sit up.

She looked again at the other person in the room. It was not Natsu; blond hair instead of pink, round belly instead of a lean torso and most of all, her butler didn't have curly moustache.

Right, she remembered now. She was kidnapped by Baron Everlue. That would explain why she woke up lying on the tiled floor, arms bound by thick leather to her side and why there's a continuous throbbing at the back of head. Other than that, there was nothing wrong on her. Her feet were not bound so she can stand up and run if ever she needed to move.

Her kidnapper's footsteps clicked loudly. "Good evening." He greeted in that impossibly grating sing-song voice.

She shot him the sharpest glare she could give. Having just woken up and hurting all over didn't exactly give her the best mood for entertaining a villain with a curly moustache. "Drop the formalities. There's nothing good in the evening."

Everlue chuckled, greatly amused at Lucy's sharp tongue. "Relax, Earl. We have the whole evening to talk."

Lucy groaned loudly and rolled her eyes in irritation. "Do I have a choice in the matter?"

"If you behave and cooperate with me, I'll let you off quickly." He stroked at his moustache and gave her his most business-like smile. "Now, about the men I sent out to deliver my little toys, where are they?"

Lucy looked away quick. "I left it to Commissioner Redfox to round them up behind the bars. And revolvers and shotguns hardly count as toys."

"Hmmmm." Everlue hummed as he continued to stroke moustache repeatedly. "That's a problem for me, boyo. I'm sure my boys won't sell me out but I need them and the items they were holding. So how about it, Earl? Release my men you put to prison and let me bring in those weapons once and for all, yes?"

She stuck out her pink little tongue at him. "I don't deal with men with idiotic curly moustaches." It was quite childish but she deemed it worth breaking lady etiquette when he bristled at her insult.

His face crumpled into a very dark scowl. He crouched down to her eye-level and grabbed her by the chin. "Watch your tongue, little girl. I don't care if you're the Queen's Watchdog, ruler of Fiore's Underworld or whatever evil nickname you have. You're just a helpless little girl without your title."

"And you're just a bitter old man who can't accept that a little girl stopped him from importing weapons in." Lucy smirked, even if it was painful under Everlue's vise grip. "So you kidnapped me as revenge."

"Y-YOU–!"

Lucy's cheek stung where he hit her. She even tasted blood in her mouth. She must have bitten her inner cheek when he slapped her.

Then Everlue pushed her to the floor and sat on top of her. She felt the wind knocked out of her for the second time of the day. He was heavy.

"I'll teach you a lesson little bitch." Another slap, this time on the other cheek. "Queen's Watchdog? Bah! I can't believe Fiore is scared of a girl! What can you even do?" He pulled her up by her collar. "You'll do better by spreading those legs for me and scream!" he shouted as he ripped her dress. Buttons clattered on the floor as the tear got larger and exposed much of her chest.

Lucy shivered violently as memories rushed in. Intoxicating fumes and the cold floor; the smell of sizzling flesh as the red, hot metal touched her skin and the endless chanting of the men. She was back in that place, alone and powerless. She wanted to cry and scream. She wanted to die already.

It was only when she heard the sound of glass shattering did she come back to her senses. Her body stopped shaking and her hear beat returned to normal. "I'm okay. I'm okay." She told herself. "I am not alone now."

Everlue snapped out of his rage fit as well and got off her. "What was that?"

"Tch, he's late." Lucy said irritably.

Everlue looked back at her, eyes slanting in suspicion. "What was that?" he asked again.

He almost jumped when someone knocked on the door. Very slowly, the door opened, revealing a young man in black tail coat and pink hair. The Heartfilia Butler pin sparkled on his breast pocket.

"You in there, Lady Lucy?" Natsu asked.

Lucy turned her face sideward to face her butler. "You're late."

"Sorry," he lifted a hand to the back of his head and chuckled, "I got busy on the way."

"H-how? How could you be here?" Everlue asked, pointing a shaking finger at Natsu. "You can't possibly be here! My men should have killed you at the manor."

Natsu continued to walk towards them. "Those two? There weren't much of a challenge. Bo-o-ring."

"H-how did you get past the guards here?!" Everlue stepped back, visibly disturbed. "I had 50 men standing guard outside!"

"I slipped in through the window and then played darts and bullet pinball with them. It was fun with moving targets! Think I beat my personal high score right there." He answered playfully. "Then I heard Lady Lucy crying in this room, so I came to get her."

"I was not crying." Lucy scoffed.

Natsu paused on his tracks. "You were not?"

"No." she asserted. "I was not crying."

"Ehhh," Natsu pouted, "I thought the plan said you're gonna cry and call for me."

"There was no such thing in the plan." Lucy glared at him.

Everlue couldn't believe his eyes. How could they banter like that as if there's nothing wrong in the world? "W-what is this plan ~boyo? What are you talking about?"

"As you've said, your men won't sing. The police knew you're the one behind those illegal deals but they couldn't get enough evidence although the Queen wanted little upstarts like you behind bars immediately. So we just made you commit another crime." Lucy answered.

"Lord Everlue," Natsu called out as he walked further into the room. "Did you know kidnapping and assaulting the current head of a noble family will land you in prison?"

"You tricked me into this?" the Baron backed even further to the corner of the room. Something about the pink haired butler frightened him. A sinister aura surrounded him, something that was missing earlier in the manor. His playful act was outright terrifying.

Natsu crossed his arms and hummed. "That's a heavy accusation, my Lord. I wouldn't say we tricked you. We just knew you love attending parties. So Lady Lucy used that to her advantage. She figured you won't be able to resist a party invitation to the Heartfilia Manor since it's your perfect chance for revenge! But we gave you the wrong day so you'll be a week early."

"So you really tricked me ~boyo!" Everlue stomped his foot indignantly.

Lucy thought it was hilarious and very out of character for the man who was just harassing her moments ago to get swept by Natsu humor. Well, no one really gets away when her butler starts playing.

"You should have realized that." Lucy cut in. "No one in their right mind will organize a party on a Monday night. It must be the moustache."

Everlue turned ten shades of red in anger and his shook uncontrollably. "You'll pay for this ~ boyo!" He pulled out the revolver from his coat fired full rounds at both Natsu and Lucy.

Bullets zipped all over the room, leaving Natsu no choice but to move quickly. The baron was relentless; he was actually carrying two guns with him. Once the revolver used up all its rounds, he pulled out a handgun from his belt holster. A bullet almost got Lucy but thanks to Natsu's agility, he managed to scoop her up in time, bridal-style, and dodge the remaining barrage of bullets. It was a total chaos. All furniture in the room had a new hole or two on them afterwards.

It was silent except for the Baron's heaving. Natsu then decided that it was safe to set down his mistress for the moment. "That was incredible!" he said as he helped her stand. He immediately worked on her bindings as well, using his bare hands to break the ropes.

Lucy's shoulder and wrists popped softly when she rolled once they were free. "I can't believe you're enjoying this." she told him.

"Hmm?" Natsu grinned at her. "It's part of why I love working for you, milady." He fussed with her hair and bent down to whisper directly to her ear. "Aside from the extra benefits, of course."

"Y-you stop that!" She swatted at his hand away from her hair. Her cheeks were burning from his whispered words and she was greatly reminded of her state of undress. She desperately pulled the torn fabric together to hide her exposed chest.

Her embarrassed glare left Natsu laughing out loud which infuriated her even more.

But the other man in the room was a lot angrier than her. The handgun rattled loudly in his trembling hands. "W-who are you people?" he asked them again. His eyes were wild, terribly terrified from what he just witnessed. "You," he pointed at Natsu, "you're not normal."

Natsu shook a finger at him and clicked his tongue. "Now, that's very rude Lord Everlue. You don't tell people they're not normal right in the face. I'm just one hell of a butler."

"I know I got you twice!" His voice broke mid sentence. "In the head! How are you still standing?"

"You meant this?" He slipped a hand in his breast pocket and produced two bullets. "Painful little bugs, really. Do you need them back?"

Lucy put a hand on Natsu's shoulder and looked at him sternly. "Stop. You're scaring him so much already, poor thing."

"You're not normal either." Everlue spat at her, almost shouting now. "I-I don't know how, but you're not normal."

Lucy giggled and leaned her head on Natsu's shoulder. "As the Queen's Watchdog, I've been called a lot of different things. Getting called "not normal" is actually the kindest way to put it. But that won't exempt you from your crimes."

"What crimes? You set this all up!" He gestured wildly both at Lucy and around the room.

But Lucy was not someone who easily relents. She just looked straight into his eyes. "I learned a lot about you during our investigations. Coercion, drug pushing, smuggling and even murder; you showed up in numerous cases of as a suspect. You only managed to stay out of prison all this time because the police could not find enough evidence. But no one escapes from the Watchdog's nose. It's over Baron Everlue." Her eyes burned in the silence that followed until the baron finally looked away.

Admitting defeat, Everlue sighed and dropped his head. His shoulders shook as he started to laugh. "Yes, I now realize I can't win against you, Earl Heartfilia." He dropped his handgun on the floor as well. "But I still have one trick up my sleeve, something that will require you to update your list."

Lucy and Natsu watched silently as he slowly walked to one of the ruined cabinets and opened one drawer. From it he got a candlestick and a matchbox and laid them on top of the drawer. He lit the candle and the smell of burning phosphorus permeated in the room. When he turned around to face them again, the dancing flame gave his smile an eerie glint. "Please add 'arson' on that list."

It happened like slow-motion. The candlestick spun in the air, the flame a little light show of its own. It landed on the silk curtain and quickly set the tapestry on fire. The flames quickly spread and in just a few seconds, one side of the room is already engulfed in orange flames. Everlue stood in the middle of it all, cackling. "If bullets can't kill you, then maybe fire can. If I can't make it out here anyway, then I'll just take you to hell with me!"

"Then you leave me no choice." Lucy said coldly. With her left hand currently occupied, she pulled the glove off her right hand with her lips. With the glove off, it revealed the Faustian contract etched on the back of her hand. The blood seal glowed amongst the shadows.

With a clear voice, she uttered her words of power. _"Natsu, this is an order. Put off this fire and stop Everlue."_

A wide grin split Natsu's lips. He felt power surge within him, the contract energizing every vein in his body. It was a high he will never tired of. He slowly unwound the white-scaled scarf he always wore, revealing the seal of their contract on the right side of his neck. He then wrapped it around his mistress, covering up the exposed skin she's been struggling to hide. It delighted him when her eyes grew wide in surprise that slowly turned into a soft smile. He then took her hand and kissed it.

 _"Yes, My Lady."_ was his answer to her order.

Lucy was captivated once again at how his usual charcoal eyes turn into red embers every time his true powers were on play.

"The scarf is fireproof." He told her as he gave her hand one last squeeze. Lucy nodded as she pulled it closer to her body. It smelled so much like him: a strange combination of tea, cinnamon and woodsmoke. Strange, not totally unpleasant. _"It stinks."_ is what she thought as she watched him subdue Everlue in the sea of raging flames.

Later that night at the Magnolia Police interrogation room, the wild-eyed and deeply terrified Baron Everlue confessed to all his crimes. He willingly gave all the location of the warehouses where he kept his smuggled guns and admitted to co-owning an opium den. He even promised to tell the police all the names of his associates, nobles and commoners, in his illegal businesses, as long as he's kept safe and away from the Queen's Watchdog and her demonic butler.

The officers thought he was crazy, unaware of the reality of the Underworld. But Everlue knew better now. He's learned his lesson.

 _"Beware of the Watchdog."_ He thought bitterly.


End file.
